The application of dental restorations to the teeth of patients requires the use of specially formulated dental adhesives that will be effective to form a bond with a surface of the patient's dental anatomy. The more effective of the adhesives currently having the most widespread use include resins that are applied to a tooth surface, for example, and then cured with ultraviolet or visible light. With certain formulations of such light cure adhesives, a small amount of such light is sufficient to start an adhesive curing reaction that will propagate through the entire dose of adhesive. Other types of adhesives require larger exposures to such light for the cure of the entire body of the adhesive. Such adhesives are used for the bonding of more transparent or semi-transparent restorations, such as direct restorations, veneers and other thin, small or in situ formed composite restorations.
The more effective of the dental adhesives for the uses discussed above have been provided to dentists in multiple parts. The various parts of these multi-part adhesive systems take advantage of the different properties at different parts of the system at the different stages of their use. A first part of the system may include, for example a primer, which is painted onto an area of the tooth to which the restoration is to be attached. The primer dries the surface and penetrates to form a basis for an effective bond. A second part may include a filled or an unfilled resin that is applied over the first part to interact with it and form a bond. In some forms, the second part is itself supplied in two parts. In a superior form a subpart of the second part is a resin and the other subpart is a fill material in the form of minute glass beads. The fill, which is mixed to a content of about 48% of the mixture with the resin, contributes strength and shock absorbency to the bond. Multi-part adhesives of this type are available in an alcohol base and marketed under the trademarks Optibond and Optibond FL by Kerr Dental Materials Center of Orange, Calif.
The application of each part of the multi-part adhesive system by a dentist calls for the coating of a small area of a patient's tooth, for example, with a small quantity of each part of the adhesive system being applied. The coating with each adhesive part is followed by the placement of the restoration, which may be a restoration formed in a dental laboratory on a model of the patient's teeth that is transferred by the dentist onto the patient's dental anatomy or may be a restoration formed in situ by the dentist, usually from a composite material. The different parts of the multi-part adhesive systems are traditionally packaged in containers designed to hold a quantity of material sufficient for bonding multiple restorations and which can be resealed after each use. In a one part adhesive, a single container designed to hold a quantity of material sufficient for bonding multiple restorations in the treatment of multiple patients and which can be resealed after each use is used. To use such containers, the dentist or dental assistant is required to retrieve the containers for each part of the adhesive system from a storage area, open each container, dispense from each container into another container (typically a container which constitutes an open well) the required amount of the adhesive part being dispensed, reseal each container for each adhesive part and return the containers to the storage area.
To reduce the time and effort associated with administering adhesives provided in bulk containers, adhesive dispensers having pre-measured doses of adhesives have been developed. Prior art dispensers for delivering pre-measured doses of dental adhesives for use by a practitioner have been provided as trays or pouches having one or more wells for containing the adhesive components and an applicator which is partially secured within the tray or pouch. One example of this type of dispenser is shown in U.S. Pat. No. 6,328,159 to Discko, Jr. In these types of dispensers, the applicator may be removed from the dispenser by prying the cover off using the applicator for leverage, whereby the wells containing the adhesive components may be accessed with the applicator. Alternatively, the adhesive components may be squeezed from the adhesive-containing wells to an applicator well whereafter the applicator is pulled from the dispenser to apply the adhesive. One drawback of these types of dispensers is that the applicator tip may be damaged when the applicator is used to remove the cover from the dispenser to expose the adhesive wells. On the other hand, when the adhesive wells are squeezed to extrude the adhesive components into an applicator well, not all of the components may be dispensed into the applicator well, resulting in wasted adhesive. Moreover, when the dispenser cover is removed to expose the adhesive wells, the adhesive components are exposed to the environment, thereby increasing the potential for contamination.
There is thus a need for an adhesive dispenser which can be used to dispense a single dose of dental adhesive having one or more components and which overcomes drawbacks of the prior art, such as those discussed above.